KR20100103475A - Coordinated change of transmission parameters for data and control information - Google Patents

Abstract

The present invention provides a method for transmitting control information from a primary station to at least one secondary station, the control information being transmitted together with the first set of control information parameters in response to the data transmission with the first set of data parameters. And transmitting control information together with the second set of control information parameters in response to data transmission with the second set of data parameters, wherein the at least one control information parameter comprises two sets of control information parameters. Has a difference in value between the values, the difference in value having a dependency on the difference between the value of the data parameter in the first set of data parameters and the value of the data parameter in the second set of data parameters, The control parameter being a parameter different from at least one control information parameter; It relates to a beam signaling method.

Description

Combined change of transmission parameters for data and control information {COORDINATED CHANGE OF TRANSMISSION PARAMETERS FOR DATA AND CONTROL INFORMATION}

The present invention relates to a method of signaling control information in a communication network.

The present invention relates to mobile systems such as, for example, Universal Mobile Telecommunication Network (UMTS), GSM or the like. The invention can also be applied to any other communication systems.

In a typical mobile communication system such as UMTS, a primary station such as a base station (or Node B) and a secondary station such as mobile stations communicate together by a plurality of channels. Primarily, data channels are used to transfer data from the main station to the secondary stations, and control channels are used to provide information about the operation of communication systems.

In general, when the main station wants to change the transmission parameters for the data, such as increasing the transmit power of the signals transmitted on the data channels, the main station applies the same increase in power for the control channel. .

However, this causes an increase in interference for all secondary stations and does not always allow the most appropriate parameter correction to be performed.

In particular, in systems where secondary stations are able to apply specific beamforming for data transmissions (in UMTS LTE), the range of coverage for data transmissions for beamforming transmissions compared to other transmissions in normal mode. Increases. However, if control signaling indicative of data transmission parameters (especially time-frequency resources and a modulation and coding scheme (MCS)) is unreliable, then it is sufficient for the secondary station to know how to decode the data. As long as the information cannot be received (even if the SNR has enough information for decoding), an increase in coverage for the data would not be advantageous.

One solution is to apply beamforming to the control channel as well. However, in systems such as LTE having a common control channel that includes control signaling for multiple secondary stations, beamforming is specific because pilot symbols embedded in the control channel are common to all secondary stations, i.e. Regardless of whether data transmissions to the secondary stations use beamforming or not, they cannot be readily used for transmission of the control channel because they are used as the phase reference for decoding control signaling by all secondary stations. . As a result, the pilot symbols in the control channel cannot use beamforming (otherwise the control channels will not provide accurate phase reference for substations that do not use beamforming), and thus the beamforming will not provide some substations. If applied to control signaling for these subcarriers, there is no suitable beamformed phase reference for control signaling for these secondary stations.

It is an object of the present invention to propose a method for the transmission of control information which allows to reduce interference by using different transmission parameters from data transmission.

Another object of the present invention is to propose a method of transmitting control information to a plurality of sub stations, in which data transmissions to some sub stations are operated by beamforming.

To this end, in accordance with the present invention, a method for transmitting control information from a primary station to at least one secondary station, the method comprising: together with the first set of control information parameters corresponding to data transmission with the first set of data parameters; Transmitting control information and transmitting control information together with the second set of control information parameters in response to data transmission with the second set of data parameters, the at least one control information parameter being two sets Has a difference in value between the control information parameters of the two, the difference in value being dependent on the difference between the value of the data parameter in the first set of data parameters and the value of the data parameter in the second set of data parameters. Wherein the data parameter is a parameter different from at least one control information parameter The control information transmission method is proposed.

As a result, if the data parameter is changed, it is possible to select a change of different control parameters in order to prevent an increase in interference resulting from transmission of the control channel. For example, when the transmit power is increased for data transmission with the secondary station, the corresponding parameter change in signaling control information may reduce the code rate for the information to be signaled to the considered secondary station.

In particular, the present invention has the advantage that by linking the change of the control parameter to the change of the data parameter in a coordinated manner, a waste of transmission capacity or unnecessary interference compared to the case where the parameter changes are not adjusted.

In an embodiment of the invention, there is also provided a method for transmission of control information from a primary station to at least one secondary station, the method comprising transmitting control information with a set of parameters, wherein the parameters of the set are at least With the dependency on the data transmission mode to one secondary station, the control information transmission method is proposed, wherein the data transmission mode is one of a beamforming transmission mode and a normal mode.

This then allows to obtain the same increase in the range obtained by using beamforming for the data channel but not using the beamforming of the control channel.

The invention also relates to a secondary station comprising means for carrying out the method according to the invention.

The invention also relates to a main station comprising means for carrying out the method according to the invention.

These and other aspects of the invention will become more apparent and apparent with reference to the embodiments described below.

The invention will now be described in more detail by way of example with reference to the accompanying drawings.

The present invention proposes a method for transmission of control information that allows to reduce interference by using different transmission parameters from data transmission.

The present invention proposes a method of transmitting control information to a plurality of sub stations, in which data transmissions to some sub stations are operated by beamforming.

1 is a block diagram representing a network comprising a primary station and a secondary station in accordance with the present invention.
2 is a representation of coverages corresponding to each transmission mode in accordance with the present invention;

The present invention, as shown in FIG. 1, includes a main station 100, such as a base station or an evolved Node B (eNode B), and at least one secondary station, such as a mobile station or user equipment (also represented as a UE). And a communication system 300 comprising a).

Wireless system 300 may include a plurality of primary stations 100 and / or a plurality of secondary stations 200. The main station 100 comprises a transmitter means 110 and a receiving means 120. The output of the transmitter means 110 and the input of the receiver means 120 are coupled by the coupling means 140 to an antenna array 130 which may comprise a plurality of antennas, the coupling means being a circulator, for example. It can be a circulator or a changeover switch. The control means 150 coupled to the transmitter means 110 and the receiving means 120 may for example be a processor. The secondary station 200 comprises a transmitter means 210 and a receiver means 220. The output of the transmitter means 210 and the input of the receiver means 220 are coupled by a coupling means 240 to an antenna array 230 which may comprise a plurality of antennas, the coupling means being for example a circulator or It can be a changeover switch. The control means 250 coupled to the transmitter means 210 and the receiving means 220 may be a processor, for example. The transmission from the primary wireless station 100 to the secondary station 200 occurs on the first set of channels 160, and the transmission from the secondary wireless station 200 to the primary station 100 takes the second set of channels. Occur on field 260.

In the first embodiment of the present invention, the primary station can transmit data to the secondary station according to several different modes. In each mode, a plurality of sets of transmission data parameters are selected. If the main station wants to change from the first mode to another mode, for example, to reach higher throughput or increase the range of transmission, at least one data parameter is changed.

In various variations of the invention, the corrected data parameter is:

Beamforming mode or multiple antennas, or multiple data streams,

-Transmission power,

-Code rate,

Modulation scheme,

Transmission diversity scheme,

Multiple space layers,

Precoding matrix,

Multiple subcarriers,

-Frequency band,

May include at least one of the spreading factors.

Similarly, control information is transmitted with different sets of control parameters, each set corresponding to a data transmission mode. When the main station is switched from the first mode to the second mode, a modification of the transmission for at least one data parameter is executed, and a corresponding modification of the at least one control parameter is likewise automatically executed. However, according to the invention, the corrected control parameter is in a form different from that of the corrected data parameter.

For example, switching from the first mode to the second mode may include an increase in the number of subcarriers of the data signal and an increase in the code rate of the control information.

In the case where the second set of data parameters is selected to change the communication range of the data transmission compared to the first set of data parameters, the selection of the second set of control parameters can be done in a smart manner. This is the case, for example, when the transmit power is increased (the overall coverage is increased) or beamforming is applied (the range is increased in a single direction). This is then advantageous if the second set of control information parameters are selected to also change the communication range of the control information in comparison with the first set of control information parameters. In such a case, the range of control information can be increased if the range of data communication is also increased due to switching from one mode to another mode. Control parameter values may be selected or the change in the communication range of the control information may be determined to approximately correspond to the change in the communication range of the data transmission.

In the previous example, the illustrated method is particularly suitable when the first mode is a regular mode (eg, single antenna transmission) and the second mode is a data beamforming mode. This beamforming mode causes an increase in the data communication range in at least one direction.

In order to reduce interference and to avoid perturbation of pilot symbols embedded in the control channels due to phase shifts, the control information is not beamformed but is transmitted at a reduced code rate, for example. Thus, control transmission is more robust to interference and can be decoded more extensively.

This example is shown in FIG. 2, where the base station 100 first operates in the first mode, which is the normal mode, not the beamforming mode. In this mode, data and signaling coverage is known as 10 and allows to reach mobile stations 201 and 202. However, in order to reach the mobile station 203, the coverage must be changed. Thereafter, the base station 100 begins to transmit in the beamforming mode, where the transmission beam is directed to the mobile station 203. In such a case, data coverage is known as 20 and allows to reach secondary station 203. Moreover, since the control signal for the secondary station 203 cannot be beamformed as previously described, the base station 100 transmits this control signal by using a lower rate or a lower frequency band, thereby covering the coverage. Allowed to increase. In that case, control signal coverage, known as 30, allows to reach the secondary station 203. Moreover, by reducing the code rate rather than increasing the transmit power of the control signal, this avoids increasing interference.

In this example, the code rate of the control signal is selected during the second mode such that the range of the control signal is equal to or greater than the range of the data signal during the second mode.

In the example of this embodiment, the control information is coded into messages of size selected from a set of predetermined control message sizes. Indeed, in current proposals for LTE, control signaling for each secondary station is coded into one of the set of available control channel message sizes. Then, the code rate of the control signaling for the secondary station whose data transmission was beamforming was reduced so that the number of coded bits could be mapped to a message size larger than the signaling information for the sub station whose data transmission was not beamforming. Could.

In various examples of the invention, the modified control parameter may be one of the following:

Modulation order;

-Transmission power;

Reduced code rate.

According to the invention, one or more transmission parameters of control signaling corresponding to data transmission using beamforming are adjusted for transmission parameters of control signaling corresponding to data transmissions not using beamforming.

This allows the coverage of the control channel to be increased to substantially match the coverage of the data channel. Advantageously, the adjustment of the transmission parameters is designed to provide a substantially similar increase in coverage obtained by the application of beamforming. Adjustment of transmission parameters could include, for example, one or more of the following:

Code rate reduction;

Modulation order reduction;

● Increased transmit power.

In another embodiment, the base station may transmit in two frequency bands (eg, 900 MHz and 2.1 GHz). Due to the differences in radio propagation, the coverage increases with lower frequency bands. Thus, to maintain coverage, beamforming is applied for transmissions to higher frequency bands. If the control channel is sent from the base station in the lower frequency band, the data channel may be sent in the same frequency band or in a higher frequency band. In this case, according to the present invention, beamforming is applied to the data channel transmitted in the higher frequency band. If the control channel is transmitted in a higher frequency band, one or more transmission parameters of the control channel are adjusted to maintain similar coverage achieved with high or low frequency bands by beamforming.

Note that the present invention is not limited to mobile communication systems such as LTE of UMTS, but is also applicable to other standards such as the evolution of WiMAX or cdma2000.

Indeed, the invention is not limited to the mobile communication systems described by way of example herein and may be extended to any other communication systems.

In this specification and claims, the singular terms preceding the element do not exclude the presence of a plurality of such elements. Also, the word “comprising” does not exclude the presence of elements or steps other than the listed elements or steps.

Although the present invention has been primarily described with respect to signaling and data transmissions made by a network entity for a mobile terminal, it will be understood that the present invention is equally applicable to opposing or other applications of the roles of nodes.

By reading the present disclosure, other modifications will be apparent to those skilled in the art. Such modifications may relate to other features that are already known in the wireless communications field and transmitter power control arts and that may be used in place of or in addition to the features already described herein.

10: data and signaling coverage 20: data coverage
30: control signal coverage 100: base station
201, 202, 203: Mobile stations

Claims (12)

A method for signaling control information from a primary station to at least one secondary station:
Transmitting control information together with the first set of control information parameters in response to data transmission with the first set of data parameters and controlling the second set in correspondence with the data transmission with the second set of data parameters. Transmitting control information along with the information parameters,
At least one control information parameter has a difference in value between the two sets of control information parameters, the difference in value being the value of the data parameter in the first set of data parameters and the second set of data parameters. Having a dependency on a difference between values of a data parameter in, wherein the data parameter is a different parameter from the at least one control information parameter. The method of claim 1,
The data parameter may be at least one of a beamforming mode, a transmit power, a code rate, a modulation scheme, a transmit diversity scheme, a plurality of spatial layers, a precoding matrix, a plurality of subcarriers, a frequency band, and a spreading factor. Control information signaling method. The method according to claim 1 or 2,
And the second set of data parameters is generated to change a communication range of the data transmission compared to the first set of data parameters. The method of claim 3, wherein
And the second set of control information parameters is generated to change a communication range of the control information compared to the first set of control information parameters. The method of claim 4, wherein
The change of the communication range of the control information corresponds approximately to the change of the communication range of the data transmission. The method of claim 3, wherein
And the data parameter is a beamforming mode and the change in communication range is an increase. The method according to any one of claims 1 to 6,
And the at least one control information parameter is a transport code rate. The method of claim 7, wherein
And wherein the value of the transmission code rate is lower in the second set of control information parameters than the first set of control information parameters. The method of claim 8,
The control information is a message of a size selected from a set of at least two predetermined control message sizes, and the selection of a low value of the transmission code rate is such that coded information bits use the first set of control information parameters. A control information signaling method executed to fit a message size larger than the message size for the transmitted control information. The method according to any one of claims 1 to 9,
And the at least one control information parameter is a modulation order. The method according to any one of claims 1 to 10,
And the at least one control information parameter is a transmit power. The method according to any one of claims 1 to 11,
And the at least one control information parameter is a frequency band.

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